In addition to northern Australia, eastern Siberia and Oklahoma and the U.S. Southwest, many native languages are endangered in South America -- Ecuador, Colombia, Peru, Brazil and Bolivia -- as well as the Pacific Northwest, including British Columbia, Washington and Oregon.

"When we lose a language, we lose centuries of human thinking about time, seasons, sea creatures, reindeer, edible flowers, mathematics, landscapes, myths, music, the unknown and the everyday."

As many as half of the current languages have never been written down, he estimated.

That means, if the last speaker of many of these vanished tomorrow, the language would be lost because there is no dictionary, no literature, no text of any kind, he said.

Harrison is associate director of the Living Tongues Institute based in Salem, Ore. He and institute Director Gregory Anderson analyzed the top regions for disappearing languages.

Anderson said languages become endangered when a community decides that its language is an impediment. The children may be first to do this, he explained, realizing that other more widely spoken languages are more useful.

Harrison said that the 83 most widely spoken languages account for about 80 percent of the world's population while the 3,500 smallest languages account for just 0.2 percent of the world's people.